300 watt sockets? So now I need a high power DC power supply with a fan in every outlet?
Someone is not thinking this through all the way. Even at 90% efficiency you are wasting 33 watts of energy at max, and that is a LOT of heat to generate behind a wall with no ventilation.
Not to mention the power supply is not going to fit in a standard box. Or that good (read: Efficient) DC power supplies are quite expensive.
And you won't be making central power supplies in the basement either. 300 watts at 12 volts is 25 amps! You would need pretty thick cables to do that. At 5 volts it's 60 amps - that would be a wire as thick as what an electrical dryer uses.
He can have as many dreamy smiles as he wants, but this is not going to happen.
What if we chose a voltage that could be transmitted throughout the house without too many issues -- like 48V?
Then we could step that down in the sockets, to 12 and 5V.
We could also use USB cables that have transformers built in, I guess -- bulges in the cable, or something. But then you're moving away from the 'one cable for everything' idea.
I like this idea.. I've actually been thinking about something like this for a while.
You could have a DC distribution panel next to the main one, that converts the mains voltage to 24/48 VDC for lighting circuits and DC receptacles. 240 Watts (10 or 5 Amps) could be enough to power a lot of devices on a branch, while still allowing the wires to be reasonable (14 AWG or smaller).
I think the bigger win would be for LED lighting circuits, but device chargers could use it too.
Why? I can't see any gain to converting to 48 volts if you just have to convert it again anyway. There isn't much difference between converting from 120 vs 48.
This looks like a marvelous way to get user data. How much do you trust every USB plug you use? If you plug your phone/music player/tablet into a USB "charger" could it pretend to be a host computer, and get access to all your files without you knowing?
There's no way a USB plug will replace existing power outlets. A 15A line in the US can handle over 1400 W, which is more than the 100W mentioned here or the hypothetical 300W in the future. An induction cooktop draws around 2000W and an electric oven around 7500W.
Plus, a number of devices depend on AC power to drive a induction motor, so there's a huge installed base that can't cheaply be replaced with DC power even there's enough raw power available.
Most of the devices I have enable you to decide how to use the USB connection. For example, on most Nokia phones you can choose between "charging only", "PC suite mode", and "USB mass storage".
I think my ICS Transformer Prime only provides "media device" and "digital camera" as modes, though.
Coincidentally, it's the other way around with USB dead drops.[1] Either trust that the USB won't fry your motherboard or carry a multimeter with you all the time.
Ouch. I'd thought of the malware risk of plugging into a dead drop, but it never quite crossed my mind that someone could basically turn one into the equivalent of the Etherkiller:
I suspect some hubs would be suitable for buffering against that sort of attack. Not sure which though, or whether a more subtle approach (some sort of pulsed power to avoid tripping polyfuses, perhaps) would still be practical.
If you wanted to be a dick, I think replacing the insides of a USB stick with a large charged capacitor and leaving them in parking lots would be the way to go.
When I built my office last year, I tried to find USB sockets and couldn't. It was like they didn't exist. I didn't even want ones that could supply a tonne of power, just a bare minimum would be sufficient.
In the end I retro fitting a hub to the wall that connected to my system which is hidden in the wall ,with the cables running under the wooden flooring.
If you have many USB ports, could you wire something up to run a television from multiple USB 5V ports or is there a voltage/amp issue of some kind in the way?
Depends on how much power the TV took. Theoretically you could do it, but it would be a huge waste.
Suppose you have a 300 watt plasma TV - that's 60 amps at 5 volts. That's the kind of wire electric dryers and ovens use. You could take that wire and divide it into many small ones, but you would still have that much wire which would not be practical.
However, an individual connector may be rated to 100 watts, but the controller may not be able to deliver 100 watts to each of the ports it is connected to. You might have to span the TV across several different hubs.
However much current you can draw over your USB socket, it's still only 5V. Many devices want a (far) higher voltage than that for charging or powering themselves. A quick glance at my laptop PSU shows 20V, presumably related to the voltage of several Lithium Ion cells in series.
Yes, a given psu could transform the voltage back up with switchmode, but then you've got the horrible transformation inefficiency twice!
I wonder how many devices there are out there that actually want that much current at 5V.
Ignore the power issues and think about the security issues. Would you give some random plug in the wall hardware access to your smartphone along the same cable that data goes?
Is experimenting a wasted effort? Is an experimenter really working against other experimenters? Is there a better way to choose a solution to (virtually any) problem than to test multiple solutions? I don't think there is, at least not without some kind of omniscience.
Sure, experimenting is a great way to reach an optimum solution to a given problem.
Now please, go to your cellar and tell me for what kind of experiment are those 40+ different chargers that you have for all your devices, which most of them have exactly the same power requirements.
I would say that, in most cases, those chargers were developed in order to take that extra 1 EUR profit.
And that, *ing the customer, which somehow has been taking this mess for over 20 years.
> go to your cellar and tell me for what kind of experiment are those 40+ different chargers that you have for all your devices
Right now I can charge almost all my mobile devices (a phone, an mp3 player, a kindle and the batteries for my camera) with a single charger I picked up in a regular department store for ~15EUR (first set of rechargeable batteries included) and two standard usb cables which came with those devices and can also be used to transfer data. More, the charger is largely optional, I could just plug them into into my computer -- often connecting to put podcasts on is enough to charge the mp3 player.
Only my laptop really requires a separate, dedicated power supply. The 40+ different chargers are just remnants of my electronic history because the current generation of mobile devices didn't even come with the chargers (except for the htc phone, but it's a standard usb charger, I could use it with cables and devices other than the phone).
The experimentation phase is largely over and makers are converging. Sure, there will always be someone who diverges but it's the cost of progress (even if progress in this context means a prettier hole in your phone).
Without that interference in the invisible hand of the market, your cellar would be full with other 40+ chargers. All in name of 1€ profit.
Sure, it is in the interest of the manufacturers to use standardized components ... unless the customer can be fooled to take pain with minimum marketing effort. No manufacturer is going to sit down and put in their priority list the item "how to reduce the junk electronics in the basement of my customers". They must be forced to it, and if the customer is not able to unite, the voter must interfere - as is slowly happening.
> Without that interference in the invisible hand of the market, your cellar would be full with other 40+ chargers. All in name of 1€ profit.
At most my cellar would contain one additional charger for the phone. Other devices didn't come with a charger at all (some aren't even covered by the directive or were made well before its announcement). I guess in the name of 3€ of cut cost which coincidentally also reduces the number of junk electronics in my basement.
I recently stayed at a US hotel that had a couple of USB ports for charging devices. Since I don't like having to buy even more adapters just for travelling abroad, being able to charge all my devices at the same time was pretty handy. Are USB ports in hotels common in the US?
My first thought was "but only 5v?" Never heard of USB Power Delivery before. After seeing the picture, I kind of want to rig something like that up in my house.
I saw that when it was posted before, turns out you can't. There are problems with having low-power and high-power ports in the same socket, I seem to recall electricians saying it was unsafe, so you might be risking a fire with that.
Yes, that's true. It's quite illegal to mix them. You are not risking a fire, but rather a shock.
The problem is if there is a failure the high voltage might be applied to the low voltage wires which are not insulated to handle that. And neither is the user who might be touching the wire that he thinks is low voltage.
You can (I'm sure I've seen products on the market), you just need to make sure things are properly shielded such.
I believe the concern some people have with such an arrangement is wires carrying the higher power AC inducing unwanted currents in those carrying the lower power DC. How likely this actually is to be an issue I'm not sure.
That has the voltage converter (power supply) in the box. What's not legal is having a centralized power supply, and running low voltage wires from it to an existing box that also has high voltage wires in it.
Well, yeah, but running everything in your house off of a 5V USB connection is a pipe dream anyway, as was pointed out in other comments. If you simply want to plug your phone directly into a wall outlet, that can be managed.
Someone is not thinking this through all the way. Even at 90% efficiency you are wasting 33 watts of energy at max, and that is a LOT of heat to generate behind a wall with no ventilation.
Not to mention the power supply is not going to fit in a standard box. Or that good (read: Efficient) DC power supplies are quite expensive.
And you won't be making central power supplies in the basement either. 300 watts at 12 volts is 25 amps! You would need pretty thick cables to do that. At 5 volts it's 60 amps - that would be a wire as thick as what an electrical dryer uses.
He can have as many dreamy smiles as he wants, but this is not going to happen.